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Note:This page contains AI-generated content for informational and entertainment purposes only. It may contain inaccuracies. Raw event data is from USGS and EMSC. All statistics, lists, and derived information are generated by this site. Full disclaimerFound an error?
Location:
CENTRAL ITALY
Period:
12 Jul 2009 14:04:59 - 18 Jul 2009 19:44:30 (6 days 5 hours 39 minutes)
Volcanoes in 100km radius:
Colli Albani(97km)
Earthquakes:
128
16 swarms found nearby.
2007
S20070208.1(29.5km)
8 Feb
1 day 3 hours
26 earthquakes
2009
S20090330.1(25.4km)
30 Mar
98 days 16 hours
6163 earthquakes
9 May
13 days 16 hours
178 earthquakes
25 Jun
3 days 7 hours
118 earthquakes
S20090801.1(17.4km)
31 Jul
19 days 15 hours
224 earthquakes
22 Aug
6 days 9 hours
83 earthquakes
2010
30 Aug
25 days 22 hours
427 earthquakes
30 Sep
11 days 3 hours
111 earthquakes
S20101020.1(10.5km)
19 Oct
6 days 18 hours
375 earthquakes
3 Nov
6 days 0 hours
176 earthquakes
2011
S20110215.1(20.0km)
15 Feb
1 day 8 hours
27 earthquakes
5 Mar
8 days 1 hours
87 earthquakes
18 Oct
1 day 4 hours
25 earthquakes
2016
S20160824.1(29.9km)
24 Aug
15 days 11 hours
415 earthquakes
S20161030.1(16.8km)
30 Oct
3 days 20 hours
72 earthquakes
2017
18 Jan
5 days 9 hours
231 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20090713.1: Analysis of Central Italy Earthquake Activity in July 2009

Central Italy lies within one of Europe's most seismically active zones, shaped by ongoing extensional tectonics along the Apennine mountain chain. The region experiences frequent low-to-moderate magnitude earthquakes due to normal faulting associated with the stretching of the continental crust between the Adriatic and Tyrrhenian domains. This geological setting has produced a long historical record of seismic events, including destructive earthquakes in 1703, 1915, and 1997.

Swarm S20090713.1 occurred in this tectonic environment. It began at 14:04 on 12 July 2009 and concluded at 19:44 on 18 July 2009, spanning 149 hours and 39 minutes. During this period, 128 earthquakes were recorded. The first 100 events, captured between 12 and 16 July, displayed characteristic swarm behavior with no single dominant mainshock.

Magnitudes in the initial sequence ranged from 1.0 to 3.5. The strongest event reached 3.5 at a depth of 5 km on 15 July at 00:58. Other notable events included magnitudes of 3.1 at 5 km depth and multiple events of 2.9. Depths clustered predominantly between 8 and 12 km, with occasional shallower occurrences around 2–6 km. Activity showed temporal clustering, with bursts of events separated by quieter intervals, typical of fluid-driven or stress-transfer processes in extensional regimes.

The 2009 swarm fits into a broader pattern observed since 2000, during which four swarms have been documented in the same area. Earlier episodes occurred in 2007 (one swarm) and 2009 (three swarms total), underscoring the recurrent nature of clustered seismicity in Central Italy's fault network.

Such swarms contribute valuable data for understanding background seismic rates and fault interactions. Depths consistent with the upper crust align with known active faults mapped in the Apennines. Continued monitoring remains essential given the region's seismic potential.

References

  • Istituto Nazionale di Geofisica e Vulcanologia (INGV) seismic catalogs
  • Geological Survey of Italy (ISPRA) tectonic maps
  • Journal of Geophysical Research: Solid Earth publications on Apennine extension